Reinforced concrete bottom cap structure and its construction method in floodplain area

Abstract

The present invention provides a reinforced concrete bottom cap structure of a floodplain area foundation and a construction method thereof. The construction method welds concrete reinforcement to a pile foundation steel casing to make the bottom cap concrete a multi-point supported reinforced concrete slab unit, and then uses the slab unit to bear water pressure and concrete gravity, replacing the bond force between plain concrete and casing, so that the foundation clearing and bottom cap concrete construction are in a waterless working environment. Compared with traditional plain concrete, the thickness of the bottom cap concrete can be greatly reduced, thereby reducing the volume of bottom cap concrete and the volume of clearing the foundation. Furthermore, the present invention adopts a long-arm excavator and manual cooperation to clear the foundation. Compared with the water storage using a high-pressure water gun and a mud pump to clear the foundation, it can reasonably allocate resources, reduce resource investment, shorten the construction period, and speed up the construction progress.

Description

Technical Field

[0001] The invention relates to the field of bridge pedestal construction, and in particular to a reinforced concrete bottom sealing structure of a pedestal in a floodplain area and a construction method thereof. Background Art

[0002] The traditional plain concrete bottom seal mainly relies on the concrete's own weight and the bond strength between the concrete and the steel cofferdam and the steel casing to resist the water pressure formed by the head difference inside and outside the steel cofferdam. This creates a closed environment inside the cofferdam, prevents water from seeping into the cofferdam from the bottom of the cofferdam, and provides a construction platform for the foundation construction.

[0003] Traditional plain bottom-sealed concrete has the following disadvantages:

[0004] 1. The process is complicated and cumbersome, the construction is difficult and the construction period is long;

[0005] 2. There is a water head difference inside and outside the steel cofferdam (unbalanced water pressure inside and outside), which is prone to cofferdam deformation or even collapse accidents, and the safety factor is low;

[0006] 3. The complex process and working conditions increase the manpower and material investment in the force calculation of the steel cofferdam and the cofferdam observation;

[0007] 4. The thickness of the traditional plain bottom concrete is often large, so the volume of cleared foundation and bottom concrete in the cofferdam is also large, which greatly increases the investment in construction personnel and high construction costs. Summary of the invention

[0008] The purpose of the present invention is to provide a reinforced concrete bottom structure of a floodplain pedestal and a construction method thereof in view of the shortcomings of the above-mentioned construction method. The bottom concrete and the steel casing are combined into a multilaterally supported plate unit by using steel bars, and the pedestal construction load is borne in the form of plate units, thereby effectively reducing the bottom concrete thickness and the cofferdam foundation clearing thickness.

[0009] To this end, the technical solution adopted by the present invention is as follows:

[0010] The reinforced concrete bottom cap structure of the floodplain area includes:

[0011] Steel sheet pile cofferdam;

[0012] A plurality of bridge pile foundations are provided, and the plurality of bridge pile foundations are arranged at intervals at the bottom of the steel sheet pile cofferdam;

[0013] The inner support is divided into upper and lower layers and is arranged on the upper part of the steel sheet pile cofferdam, and the end of the inner support is fixed on the inner wall of the steel sheet pile cofferdam;

[0014] Stone sheets are laid on the base of the steel sheet pile cofferdam;

[0015] Bottom sealing concrete, the bottom sealing concrete is arranged on the top surface of the stone sheet;

[0016] A capping platform is arranged on the top surface of the bottom sealing concrete.

[0017] Furthermore, bottom seal concrete steel bars are horizontally laid in the bottom seal concrete.

[0018] Preferably, the bottom concrete reinforcement is connected to the steel casing by welding.

[0019] Furthermore, the inner support is composed of a plurality of steel pipes arranged in parallel or crosswise.

[0020] Furthermore, both ends of the inner support are fixed to the inner wall of the steel sheet pile cofferdam by means of steel sections and reinforced by triangular stiffening plates.

[0021] Furthermore, the bottom sealing structure also includes a drainage ditch, which is arranged between the inner side of the steel sheet pile cofferdam and the bottom sealing concrete.

[0022] The construction method of reinforced concrete bottom sealing structure of the cap in the floodplain area includes the following steps:

[0023] S1 Clear the foundation inside the steel sheet pile cofferdam and remove the silt inside the steel sheet pile cofferdam;

[0024] S2 After the steel sheet pile cofferdam foundation is cleared, the base is treated to ensure that the base of the steel sheet pile cofferdam has a certain bearing capacity;

[0025] After S3 base treatment is completed, the bottom concrete reinforcement is laid;

[0026] S4 pours the bottom sealing concrete from downstream to upstream, vibrating while pouring;

[0027] After the S5 bottom sealing concrete is strong and the pile head of the bridge pile foundation is chiseled out, the foundation construction can then begin.

[0028] Furthermore, in step S1, the foundation clearing inside the steel sheet pile cofferdam is carried out by a combination of a long-arm excavator and manual labor.

[0029] Furthermore, in step S2, the base treatment of the steel sheet pile cofferdam is carried out by dumping and filling with stone flakes. After the base treatment is completed, its bearing capacity needs to meet the load during the construction of the bottom concrete reinforcement.

[0030] Furthermore, the construction method of the reinforced concrete bottom sealing structure of the floodplain area cap includes the following steps:

[0031] After the construction of the S1 bridge pile foundation was completed, the steel sheet pile cofferdam was driven;

[0032] S2 pumps out the water in the steel sheet pile cofferdam and installs the internal support;

[0033] After the installation of S3 internal support is completed, the base of the steel sheet pile cofferdam is treated with stone chips to make the base of the steel sheet pile cofferdam have a certain bearing capacity;

[0034] S4: Arrange the bottom concrete reinforcement on the top surface of the stone sheet in step S3, and connect the bottom concrete reinforcement to the steel casing by welding;

[0035] S5 pours the bottom sealing concrete from downstream to upstream, vibrating while pouring;

[0036] When the S6 bottom sealing concrete is strong enough, the pile head of the bridge pile foundation is chiseled out, and then the foundation construction can begin.

[0037] The present invention has the following beneficial effects:

[0038] 1. Simple operation: The reinforced concrete bottom seal changes the bottom seal concrete from underwater concrete to conventional concrete, reducing the construction difficulty.

[0039] 2. Controllable construction quality: The bottom seal concrete adopts conventional concrete pouring technology. The whole process from steel bar installation to concrete pouring is intuitive and controllable. Compared with underwater concrete bottom seal, it can intuitively reflect the quality of steel bar construction and concrete pouring.

[0040] 3. Economical: After adding steel bars, the thickness of the bottom concrete is reduced, the amount of base clearing is reduced, and the thickness of the bottom concrete is also reduced; at the same time, the method of using a long-arm excavator and manual labor to clear the foundation is more rational in resource allocation, reducing resource investment, shortening the construction period, and speeding up the construction progress than using a high-pressure water gun and a mud pump to clear the foundation for water storage.

[0041] 4. Wide range of applications: The use of reinforced concrete for steel cofferdam bottom sealing has the characteristics of simple operation, controllable quality, high safety, and significant economic benefits. It can be applied to the construction of steel cofferdam bottom sealing in shallow areas and is worthy of large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] Figure 1 It is the general elevation drawing of the reinforced concrete bottom cover of the floodplain area cap;

[0044] Figure 2 It is the local reinforcement arrangement diagram of the reinforced concrete bottom cover of the floodplain area.

[0045] In the figure: 1. Bridge pile foundation; 2. Steel sheet pile cofferdam; 3. Support inside the cofferdam; 4. Stone slabs; 5. Bottom sealing concrete; 6. Capping platform; 7. Bottom sealing concrete reinforcement; 8. Pile foundation steel casing. DETAILED DESCRIPTION

[0046] The following is an explanation of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0047] It should be noted that, in the present invention, the top, bottom, left and right in the figure are regarded as the top, bottom, left and right of the assembled rigid frame described in this specification.

[0048] The exemplary embodiments of the present invention are now described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0049] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0050] The technical solutions in the implementation of the present invention will be described clearly and completely below.

[0051] Implementation Method 1

[0052] The present invention provides a floodplain area cap steel cofferdam foundation pit bottom sealing structure, such as Figure 1 , Figure 2 As shown, including:

[0053] Steel sheet pile cofferdam 2;

[0054] A plurality of bridge pile foundations 1 are provided, and the plurality of bridge pile foundations 1 are arranged at intervals at the bottom of the steel sheet pile cofferdam 2;

[0055] The inner support 3 is divided into upper and lower layers and is arranged on the upper part of the steel sheet pile cofferdam 2, and the end of the inner support 3 is fixed on the inner wall of the steel sheet pile cofferdam 2;

[0056] Stone sheets 4 are laid on the base of the steel sheet pile cofferdam 2;

[0057] Bottom sealing concrete 5, the bottom sealing concrete 5 is arranged on the top surface of the stone sheet 4;

[0058] The foundation 6 is arranged on the top surface of the bottom sealing concrete 5 .

[0059] This embodiment further provides a construction method for a reinforced concrete bottom sealing structure of a floodplain cap, comprising the following steps:

[0060] S1 Clear the foundation inside the steel sheet pile cofferdam 2 and remove the silt inside the steel sheet pile cofferdam 2;

[0061] S2 After the foundation of the steel sheet pile cofferdam 2 is cleared, the base is treated to ensure that the base of the steel sheet pile cofferdam 2 has a certain bearing capacity;

[0062] After S3 base treatment is completed, the bottom concrete reinforcement 7 is laid;

[0063] S4 pours the bottom sealing concrete 5 from downstream to upstream, while pouring and vibrating;

[0064] S5: After the bottom sealing concrete 5 is strong, the pile head of the bridge pile foundation 1 is chiseled out, and then the construction of the foundation 6 can begin.

[0065] The main force system during the bottom sealing and construction of the pedestal is the vertical force balance. The conventional wading pedestal construction adopts underwater concrete bottom sealing, and the bond force between the bottom sealing concrete and the steel casing is used to balance the water pressure before concrete pouring and the gravity after the pedestal concrete is poured. There is a water head difference inside and outside the steel cofferdam (unbalanced water pressure inside and outside), which is prone to cofferdam deformation or even collapse accidents, and the safety factor is low; and the thickness of the traditional plain bottom sealing concrete is often large, so the volume of cleared foundation and bottom sealing concrete in the cofferdam is also large, which greatly increases the investment of construction personnel and high construction costs. In order to overcome this problem, the present invention provides a reinforced concrete bottom sealing construction method suitable for the construction of bridge pedestals in floodplain areas, which welds concrete steel bars to pile foundation steel casings to make the bottom sealing concrete a multi-point supported reinforced concrete slab unit, and then uses the slab unit to bear water pressure and concrete gravity, replacing the bond force between plain concrete and casing. The pedestal clearing and bottom sealing concrete construction are in a waterless working environment. Compared with traditional plain concrete, the thickness of the bottom concrete can be greatly reduced, thereby reducing the volume of bottom concrete and the volume of cleared foundation.

[0066] Implementation Method 2

[0067] The second embodiment of the present invention relates to a bottom sealing structure of a steel cofferdam foundation pit in a floodplain area, such as Figure 1 , Figure 2As shown, it includes: a steel sheet pile cofferdam 2, an inner support 3, a stone sheet 4, a bottom sealing concrete 5 and a cap 6; a plurality of bridge pile foundations 1 are arranged at intervals at the bottom of the steel sheet pile cofferdam 2; an inner support 3 is arranged on the upper part of the steel sheet pile cofferdam 2, and the inner support 3 is arranged in two layers, upper and lower, and the end of the inner support 3 is fixed on the inner wall of the steel sheet pile cofferdam 2; the stone sheet 4 is laid on the bottom of the steel sheet pile cofferdam 2; the bottom sealing concrete 5 is arranged on the top surface of the stone sheet 4; and the cap 6 is arranged on the top surface of the bottom sealing concrete 5. The use of reinforced concrete bottom sealing on the cap can reduce the depth of the steel sheet pile cofferdam and reduce the difficulty of steel sheet pile driving.

[0068] Furthermore, the steel casing 8 is used as an auxiliary measure during the construction of the bridge pile foundation 1 to isolate the soil outside the casing and ensure the quality of the reinforced concrete structure of the pile foundation.

[0069] Furthermore, the inner support 3 is composed of a plurality of parallel or cross-arranged steel pipes. Furthermore, both ends of the inner support 3 are fixed to the inner wall of the steel sheet pile cofferdam 2 through steel sections and reinforced by triangular stiffening plates.

[0070] Furthermore, the bottom sealing structure also includes a drainage ditch 9 , which is arranged between the inner side of the steel sheet pile cofferdam 2 and the bottom sealing concrete 5 .

[0071] Furthermore, bottom concrete steel bars 7 are horizontally laid in the bottom concrete 5, and the tensile strength of the steel bars is used to resist the buoyancy of water and the tensile force caused by the foundation construction load, thereby enhancing the bearing capacity of the bottom concrete. Therefore, the thickness of the bottom concrete can be reduced, saving the amount of bottom concrete engineering.

[0072] Implementation Method 3

[0073] Embodiment 3 of the present invention relates to a construction method of a reinforced concrete bottom sealing structure of a cap in a floodplain area, comprising the following steps:

[0074] S1: clearing the foundation inside the steel sheet pile cofferdam 2, excavating the silt inside the steel sheet pile cofferdam 2. Furthermore, the clearing of the foundation inside the steel sheet pile cofferdam 2 is carried out by a long arm excavator and manual labor, and the silt is cleared to below the bottom elevation of the bottom concrete;

[0075] S2 After the steel sheet pile cofferdam 2 is cleared, the base is treated to make the base of the steel sheet pile cofferdam 2 have a certain bearing capacity; because the cap is located in the floodplain area, the water head difference between the inside and outside of the steel cofferdam is small, and the local water level is even below the ground. The stratum where the bottom seal concrete is located is an impermeable layer. Therefore, the bottom seal concrete mainly bears the load during the construction of the cap and the deadweight of the cap concrete. During construction, the base treatment adopts the method of throwing and filling stones 4 to enhance the base bearing capacity. After the base treatment is completed, its bearing capacity must meet the load during the construction of the bottom seal concrete steel bars 7 (the base bearing capacity should be no less than 100KPa, that is, it can be based on the standard that an adult standing on the base does not sink significantly);

[0076] After the base treatment is completed, the bottom concrete reinforcement 7 is laid, and the reinforcement is used to enhance the tensile strength of the bottom concrete, thereby enhancing the bearing capacity of the bottom concrete; and the bottom concrete reinforcement is further connected to the pile foundation steel casing by welding, so that the pile foundation steel casing can form an effective bearing whole with the bottom concrete;

[0077] S4 pours the bottom concrete 5 from downstream to upstream. Since the thickness of the bottom concrete decreases after adding steel bars, the pouring should be carried out in full section, and the pouring should be completed in one go and vibrated to make it dense. At the same time, in order to ensure uniform pouring of concrete, the concrete is poured by using a pump truck with multiple points, and the performance of the bottom concrete should meet the slump of 160mm to 200mm.

[0078] S5: After the bottom sealing concrete 5 is strong, the pile head of the bridge pile foundation 1 is chiseled out, and then the construction of the foundation 6 can begin.

[0079] During construction, due to the small depth of the foundation, a long-arm excavator was used for foundation clearing, and manual work was performed to clean the silt around the casing and cofferdam. After the foundation was cleared, stone chips were thrown, and then steel bars were laid and bottom concrete was poured. The whole process took 5 days. Compared with water storage, the use of high-pressure water guns and mud pumps to clear the foundation and seal the bottom saved about 20 days, reduced the amount of foundation clearing by about 1,000 cubic meters, saved about 1,000 cubic meters of bottom concrete, and reduced direct economic investment by about 350,000 yuan, which won precious time for the construction of the foundation and avoided the construction of the foundation during the flood season.

[0080] Implementation Method 4

[0081] The fourth embodiment of the present invention relates to a construction method of a reinforced concrete bottom sealing structure of a cap in a floodplain area, comprising the following steps:

[0082] S1 first constructs the steel casing 8, then drills the bridge pile foundation 1, lowers the steel cage and pours concrete to complete the bridge pile foundation 1 construction; after the bridge pile foundation 1 construction is completed, the steel sheet pile cofferdam 2 is driven;

[0083] S2 pumps out the water in the steel sheet pile cofferdam 2 and installs the inner support 3;

[0084] After the installation of the S3 inner support 3 is completed, the base of the steel sheet pile cofferdam 2 is treated with stone 4 to make the base of the steel sheet pile cofferdam 2 have a certain bearing capacity;

[0085] S4: on the top surface of the stone sheet 4 in step S3, a bottom concrete reinforcement 7 is arranged, and the bottom concrete reinforcement 7 is connected to the steel casing 8 by welding;

[0086] S5 pours the bottom seal concrete 5 from downstream to upstream, while pouring and vibrating;

[0087] When the S6 bottom sealing concrete 5 is of equal strength, the pile head of the bridge pile foundation 1 is chiseled out, and then the construction of the foundation 6 can begin.

[0088] The present invention adopts reinforced concrete to seal the bottom of the steel cofferdam in the floodplain area, fully utilizes the tensile performance of the steel bars, increases the tensile capacity of the concrete, can reduce the thickness of the bottom sealing concrete, reduce the volume of the cofferdam foundation clearing, shorten the construction period, and save construction time.

[0089] The parts not specifically described in the above embodiments belong to well-known components and common structures or common means in the technical field, and will not be described in detail here.

[0090] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention; the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A construction method for reinforced concrete bottom cap structure in floodplain area, characterized in that: It includes a reinforced concrete bottom structure of a floodplain cap, and the reinforced concrete bottom structure of a floodplain cap includes: Steel sheet pile cofferdam (2); A plurality of bridge pile foundations (1) are provided, wherein the plurality of bridge pile foundations (1) are arranged at intervals at the bottom of the steel sheet pile cofferdam (2); The inner support (3) is divided into upper and lower layers and is arranged on the upper part of the steel sheet pile cofferdam (2), and the end of the inner support (3) is fixed on the inner wall of the steel sheet pile cofferdam (2); Stone sheets (4) are laid on the base of the steel sheet pile cofferdam (2); Bottom sealing concrete (5), the bottom sealing concrete (5) being arranged on the top surface of the stone sheet (4), and bottom sealing concrete steel bars (7) being horizontally laid in the bottom sealing concrete (5); A capping platform (6), the capping platform (6) being arranged on the top surface of the bottom sealing concrete (5); The construction method of the reinforced concrete bottom sealing structure of the floodplain area cap comprises the following steps: S1. clearing the steel sheet pile cofferdam (2) and removing the silt in the steel sheet pile cofferdam (2). The steel sheet pile cofferdam (2) is cleared by a long-arm excavator and manual labor to remove the silt to below the bottom elevation of the bottom concrete (5); S2. After the steel sheet pile cofferdam (2) is cleared, the base is treated to ensure that the base of the steel sheet pile cofferdam (2) has a certain bearing capacity. During construction, the base treatment adopts the method of throwing and filling stones (4) to enhance the base bearing capacity. After the base treatment is completed, its bearing capacity must meet the load during the construction of the bottom concrete reinforcement (7). The base bearing capacity should be no less than 100 KPa, based on the standard that an adult standing on the base does not sink significantly. S3. After the base treatment is completed, the bottom concrete reinforcement (7) is arranged, and the reinforcement is used to enhance the tensile strength of the bottom concrete (5), thereby enhancing the bearing capacity of the bottom concrete (5); and further the bottom concrete reinforcement (7) is welded to the pile foundation steel casing, so that the pile foundation steel casing can form an effective bearing whole with the bottom concrete (5); S4. Pour the bottom concrete (5) from downstream to upstream. Since the thickness of the bottom concrete (5) decreases after adding steel bars, the pouring should be carried out over the entire section, and the pouring should be completed in one go and vibrated to make it dense. At the same time, in order to ensure uniform pouring of concrete, the concrete is poured by using a pump truck with multiple points of material, and the performance of the bottom concrete (5) should meet the slump of 160 mm to 200 mm. S5. After the bottom concrete (5) is strong enough, the pile head of the bridge pile foundation (1) is chiseled off, and then the construction of the cap (6) can begin.

2. The construction method of the reinforced concrete bottom sealing structure of the floodplain cap according to claim 1 is characterized by: The inner support (3) is composed of a plurality of steel pipes arranged in parallel or crosswise.

3. The construction method of the reinforced concrete bottom sealing structure of the floodplain cap according to claim 1 is characterized by: Both ends of the inner support (3) are fixed to the inner wall of the steel sheet pile cofferdam (2) by means of steel sections and reinforced by means of triangular stiffening plates.

4. The construction method of the reinforced concrete bottom sealing structure of the floodplain cap according to claim 1 is characterized by: The slump of the bottom sealing concrete (5) is 160 mm to 200 mm.

5. The construction method of the reinforced concrete bottom sealing structure of the floodplain cap according to claim 1 is characterized by: The floodplain area cap reinforced concrete bottom sealing structure further comprises a drainage ditch (9), wherein the drainage ditch (9) is arranged between the inner side of the steel sheet pile cofferdam (2) and the bottom sealing concrete (5).

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